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3B Luna G3 CPAP Machine Review

Written by Ashley Wood Staff Writer
Reviewed by Dr. Sherrie Neustein Medical Reviewer
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Look & Feel

The 3B Luna G3 CPAP Machine has a sleek, functional design, with a black outer casing and transparent humidifier tank. The LCD interface is controlled with a knob, giving users access to a host of premium features, including preheat and AutoHumidity functions, as well as sleep data tracking.

Ideal For

  • People seeking a preheat function
  • Individuals who want to prevent hose and mask condensation
  • Those looking for an easy-to-use interface that has resupply reminders

Who should keep looking

  • Individuals who need APAP or BiPAP functionality
  • People who don’t need CPAP humidification
  • Those who prefer a touchscreen interface
  • Price


  • Dimensions

    10.4″ x 5.7″ x 4.5″

  • Noise Rating

    26 dBA

  • Weight

    3.75 lbs.

The Luna G3 CPAP Machine is one of the most popular devices from React Health, formerly known as 3B Medical Inc. As a continuous positive airway pressure machine, the device is designed to maintain a constant level of air pressure during the entire breathing cycle.

The Luna G3 CPAP Machine offers many premium features aimed at providing a more comfortable CPAP experience, including a built-in humidifier, integrated heated tubing, and a preheat function. The machine also has an automatic ramp setting that gradually increases the pressure, allowing you to ease into CPAP therapy.

There are several options in the Luna G3 product line. The Auto CPAP model automatically adjusts the air pressure by monitoring your breathing patterns for sleep apnea events. The Luna G3 BPAP 25A and Luna G3 BPAP 30VT are both bilevel positive airway pressure (BiPAP) machines that provide different pressure levels for inhalation and exhalation.

We’ll focus on the CPAP model, covering its features, performance, technical specifications, and who might be a good fit for the device.

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Other Models in the Luna G3 Series

  • Luna G3 Auto CPAP: Like the standard Luna G3 CPAP Machine, the G3 Auto CPAP comes equipped with a continuous positive airway pressure mode. However, the latter also features an automatic positive airway pressure (APAP) setting that automatically adjusts the pressure level based on the user’s breathing patterns.
  • Luna G3 BPAP 25A: This versatile model has both CPAP and APAP functions but also includes a BiPAP mode that increases pressure during inhalation and decreases it during exhalation. It also has an auto BiPAP mode that automatically adjusts for apneic events.
  • Luna G3 BPAP 30VT: This Luna model offers a CPAP mode and the same two BiPAP therapies offered by the 25A, though it lacks an APAP function. Instead, the 30VT includes two additional BiPAP modes. One is a timed mode that toggles between the inhalation and exhalation pressure settings at a set rate based on breaths per minute. The other uses Luna’s forced ventilation technology, which automatically delivers airflow if it detects that the user hasn’t inhaled within a set period of time.

What You Need to Know About the 3B Luna G3 CPAP Machine

Obstructive sleep apnea (OSA) is a condition involving intermittent periods of breathlessness or paused breathing during sleep due to narrowed or blocked airways. The condition is common, affecting 10% to 30% of U.S. adults

CPAP machines pull in surrounding air and pressurize it to a specific level based on the user’s prescription. The air passes through tubing connecting the machine to a CPAP mask, where it enters the airway, making breathing easier.

Most CPAP machines measure pressure in centimeters of water pressure (cm H2O). The Luna G3 CPAP Machine has a 4 to 20 cm H2O range, which can be set in increments of 0.5 cm H2O. The device also has integrated heated tubing and a built-in humidifier with a preheat function that helps moisturize the air. These elements are designed to help prevent hose and mask condensation and reduce potential side effects such as dry mouth and dry nasal passages.

Another selling point of the Luna G3 is its ramp feature. The machine starts with lower pressure and gradually increases it to the prescribed pressure level to ease the user into their nightly therapy.

Like all PAP devices, purchasing the Luna G3 CPAP Machine requires a prescription. Speak with your doctor if you think the device is right for you.

What Comes With It

The Luna G3 CPAP Machine includes a built-in humidifier and heated tubing. You’ll also receive a filter and a power cord and adapter. CPAP masks are sold separately and also require a doctor’s prescription.

Features You Might Like

The Luna G3 CPAP Machine has several features aimed at making the treatment of OSA more comfortable and user-friendly. These include adjustable ramp settings, humidity controls, heating options, and an easy-to-use interface.

CPAP Machine Size and Cost

Measuring 10.4 inches across by 5.7 inches deep and 4.5 inches tall, the Luna G3 CPAP Machine is compact enough to fit on most nightstands. The humidifier’s water chamber holds a maximum of approximately 12 fluid ounces.

Weighing in at about 3.75 pounds, the device is comparable to other CPAP machines with built-in humidifiers. While it’s heavier and bulkier than most travel CPAP machines, it’s still small enough that it won’t take up too much space in a suitcase.

The price of the Luna G3 CPAP Machine is on par with other CPAP-only models with built-in humidification systems.

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How This CPAP Machine Performs

The Luna G3 CPAP Machine comes with several features that have user comfort in mind while treating the symptoms of sleep apnea.

The LCD screen and single-knob operation make the Luna G3 user-friendly. The ability to program preheat settings and the ramp function add to the overall user experience.

The Luna G3 is designed to be compatible with almost any CPAP mask. The device’s connective tubing works whether you prefer a full-face, nasal, or nasal pillow mask.

The pressure settings for the Luna G3 span from 4 to 20 cm H2O, which is the standard range for most CPAP machines. The pressure can be increased in 0.5 cm H2O increments.

The sound level of the Luna G3 CPAP Machine is around 26 decibels when the pressure is set at 10 cm H2O. This makes it quieter than most CPAP machines, which have an average sound level of 30 decibels.

The ability to preheat the water in the humidifier tank and the heated tubing keeps the air warm, which makes breathing easier for many CPAP users. The Luna G3 features an AutoHumidity option that adjusts the humidity levels based on the room climate. Keeping the humidity at the right level helps prevent rainout, which is when condensation builds up inside the mask and tubing.

According to the manufacturer, the Luna G3’s tubing and water chamber should be cleaned daily. Use distilled water to fill the water chamber after it’s been washed and dried. Other accessories, including the mask, should also be cleaned daily per manufacturer instructions.

The machine’s cleanable components and other accessories should be washed with warm water and mild soap. Typically, the filter needs to be replaced every six months. Store the machine and its accessories out of direct sunlight.

While the Luna G3 CPAP Machine wasn’t created specifically for travel, it’s still relatively small and light and should fit in most carry-on bags. The water chamber can be removed before traveling to make the machine more compact. However, travelers should note that this model is not approved by the Federal Aviation Administration for in-flight use.

What Do Customers Have to Say About the 3B Luna G3?

Overall, most individuals who own the Luna G3 CPAP Machine like the product. Common positive comments are that the machine is quiet, easy to set up, and gathers good sleep data. 

The three primary negative complaints are that some of the functions are not explained well in the manual, the water chamber design doesn’t allow for easy cleaning, and the machine only transmits 30 days of data.

Trial, Warranty, and Shipping Policies

AvailabilityThe Luna G3 CPAP Machine is available from select authorized CPAP machine retailers. Before buying the device, you’ll need a prescription from your doctor.
ShippingThe available shipping locations, delivery timeframe, and shipping costs vary by seller. Many retailers offer free shipping within the contiguous U.S. Some assembly is required after the device arrives. The user manual has step-by-step assembly instructions.
Sleep TrialEach seller has a specific return policy. Some allow the device to be returned within a certain period, while others don’t allow any returns. In general, used CPAP machines are not eligible for return since they are considered medical devices.
WarrantyThe Luna G3 CPAP Machine has a two-year manufacturer’s warranty that covers the repair or replacement of a defective device. While most sellers follow the manufacturer’s warranty, not all do, so be sure to check the fine print before purchasing.

Medical Disclaimer: This content is for informational purposes and does not constitute medical advice. Please consult a health care provider prior to starting a new treatment or making changes to your treatment plan.

Still have questions?

Sleep apnea products can be confusing. If you need individualized assistance, send us an email at [email protected] with your questions and we'll help find the best fit for you.

Written by

Ashley Wood, Staff Writer

Ashley is a registered nurse with over 15 years of experience and holds a bachelor’s degree in nursing. It is no surprise she likes writing about health information that encourages and enables others to live their healthiest life possible. Ashley enjoys spending time with her family, reading, hiking, and photography during her free time.

Reviewed by

Dr. Sherrie Neustein, Medical Reviewer

Dr. Sherrie Neustein is a board certified Pediatrician and a Fellow of the American Academy of Pediatrics who has enjoyed over 15 years in practice. She graduated magna cum laude from Brandeis University and with honors from the Tufts University School of Medicine. Dr. Neustein completed her residency training at the Northwell Health Cohen Children’s Medical Center and an international fellowship in medical ethics.